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    <title>Document</title>
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<body>
    <script>
        const arr = [1, 2, 3, 4]
        // let result = arr.slice(2,4)
        // console.log(result);
        // console.log(arr.includes(1));
        // let str = "1:desc"
        // console.log(str.replace(/[A-z]*$/,'asc'));
        // console.log(regPassword.test('xy123456789','xy123456789'));

     arr.filter(item => item != 2)
        console.log(arr);
    a = null;
    console.log(!a);

    </script>
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